I think Nico is good for Xavi and for the way he wants to set up. Xavi always wanted widemen who can sit on the line, open space and create from ball to feet and not work in space. Probably because he doesn't know any other way, and also a tiny part of why he doesn't find Roque worthwhile. Because he needs to change his whole setup or the way he knows football for him. Well, Pep done it with Haaland, but Pep is the 1 in a million striker and Haaland is the 1 in a million poacher.
Back to Nico, we will be better with him, and clearly he hasn't reached his ceiling. When Xavi goes by transfer fee he would have more sell on value than Ferran even if he is average here, so we would likely make the 50m back. Salary wise I don't know, Bilbao notoriously pay their top 3/4 players alot and we always pay more than the market value.
Do we wait for another AML for similar price point? Well who is that? And how far away?
Personally I'd move away from this deal purely because he could have been signed for free, and Nico and ourselves owe Bilbao absolutely nothing.